Re: Queen Install. Did I do something wrong?
The problem was leaving the nuc queenless for 2 days before introducing the queen. I intro the queen 10 minutes after making the split. If you give them 2 days then they've already started queen cells of their own and usually will reject an intro queen. Next time you can inspect the nuc and remove all started queen cells when you intro the queen, and check to do the same a couple days later when you check back.
20+ years, raise my own queens, feed when needed. I treat, but have not perfected varroa management yet.